Downhole Tool String Component that is Protected from Drilling Stresses

ABSTRACT

In one aspect of the present invention, a downhole tool string component has a first and second threaded end on a mandrel, the first threaded end attached to a first sleeve and the second threaded end attached to a second sleeve. An intermediate sleeve assembly is disposed circumferentially around the mandrel and intermediate the first and second threaded ends, and the intermediate sleeve assembly is primarily isolated from stress of the first or second sleeve.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent application Ser. No. 11/841,101; which is a continuation-in-part of U.S. patent application Ser. No. 11/688,952 filed on Mar. 21, 2007 and entitled Pocket for a Downhole Tool String Component. The abovementioned reference is herein incorporated by reference for all that it discloses.

BACKGROUND OF THE INVENTION

This invention relates to downhole drilling, specifically downhole drilling for oil, gas, geothermal and horizontal drilling. More specifically, the invention relates to inherent downhole drilling stresses including compressive stress and rotary torque. While drilling, the stresses seen by the drill string may be routed through the drill string to specific components leaving others substantially stress free.

U.S. Pat. No. 7,193,526 to Hall et al, which is herein incorporated by reference for all that it contains, discloses a double shouldered downhole tool connection comprising box and pin connections having mating threads intermediate mating primary and secondary shoulders. The connection further comprises a secondary shoulder component retained in the box connection intermediate a floating component and the primary shoulders. The secondary shoulder component and the pin connection cooperate to transfer a portion of makeup load to the box connection. The downhole tool may be selected from the group consisting of drill pipe, drill collars, production pipe, and reamers. The floating component may be selected from the group consisting of electronics modules, generators, gyroscopes, power sources, and stators. The secondary shoulder component may comprises an interface to the box connection selected from the group consisting of radial grooves, axial grooves, tapered grooves, radial protrusions, axial protrusions, tapered protrusions, shoulders, and threads.

U.S. Pat. No. 7,377,315 to Hall et al, which is herein incorporated by reference for all that it contains, discloses a downhole tool string component with a tubular body and a first and second end. At least one end is adapted for axial connection to an adjacent downhole tool string component. A covering, secured at its ends to an outside diameter of the tubular body, forms an enclosure with the tubular body. The covering has a geometry such that when a stress is induced in the sleeve by bending the downhole tool string component, that stress is less than or equal to stress induced in the tubular body. The covering may be a sleeve. Further, the geometry may comprise at least one stress relief groove formed in both an inner surface and an outer surface of the covering.

BRIEF SUMMARY OF THE INVENTION

In one aspect of the present invention, a downhole tool string component has a first and second threaded end on a mandrel, the first threaded end attached to a first sleeve and the second threaded end attached to a second sleeve. An intermediate sleeve assembly is disposed circumferentially around the mandrel and intermediate the first and second threaded ends and the intermediate sleeve assembly is primarily isolated from stress of the first or second sleeve.

The intermediate sleeve assembly may comprise a stabilizer blade. The intermediate sleeve assembly may comprise at least a portion of a downhole tool bay. The downhole tool bay may be removable. The mandrel may comprise at least a portion of a downhole tool bay. The first and/or second sleeve may be more rigidly attached to the mandrel than the intermediate sleeve assembly. The first and/or second sleeve may be disposed circumferentially around a pressure vessel. An electronics bay may be disposed intermediate the pressure vessel and the first or second sleeve. The electronics bay may comprise at least one electronics bay seal, the electronics bay seal is disposed proximate an end of the electronics bay and restricts a change in pressure within the electronics bay. The electronics bay may be disposed annularly around the pressure vessel.

The tool string may comprise a first threaded anchor disposed intermediate the first sleeve and the intermediate sleeve assembly. The first threaded anchor and the first sleeve may be separated by at least 0.01 mm. A second threaded anchor may be disposed intermediate the second sleeve and the intermediate sleeve assembly. The second threaded anchor and the second sleeve may be separated by at least 0.01 mm. The pressure vessel may comprise an electrical connection with the mandrel. The pressure vessel may be slidably connected to the first sleeve or the second sleeve. The intermediate sleeve assembly may comprise at least two components that are restricted from rotating relative to each other by at least one anti-rotation pin. The anti-rotation pin may be at least partially disposed within a recess formed within the mandrel.

In another aspect of the present invention, a downhole tool string component has a first and second threaded end on a mandrel, the first threaded end attached to a first sleeve and the second end attached to a second sleeve. An intermediate sleeve assembly is disposed circumferentially around the mandrel and intermediate the first and second threaded ends. The intermediate sleeve has a tool bay and the tool bay is primarily isolated from stress of the first or second sleeve. The intermediate sleeve assembly may comprise a stabilizer blade.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective cross-sectional diagram of an embodiment of a drill string suspended in a bore hole.

FIG. 2 is a cross-sectional diagram of an embodiment of a portion of a drill string.

FIG. 3 is a cross-sectional diagram of an embodiment of a portion of a drill string.

FIG. 4 is a perspective cross-sectional diagram of an embodiment of a portion of a drill string.

FIG. 5 is a perspective diagram of an embodiment of a portion of a drill string.

FIG. 6 is a cross-sectional diagram of an embodiment of another portion of a drill string.

DETAILED DESCRIPTION OF THE INVENTION AND THE PREFERRED EMBODIMENT

FIG. 1 is a perspective diagram of an embodiment of a downhole tool string 100 suspended by a derrick 108 in a bore hole 102. A drilling assembly 103 is located at the bottom of the bore hole 102 and comprises a drill bit 104. As the drill bit 104 rotates downhole the downhole drill string 100 advances farther into the earth. The downhole drill string 100 may penetrate soft or hard subterranean formations 105. The drilling assembly 103 and/or downhole components may comprise data acquisition devices which may gather data. The data may be sent to the surface via a transmission system to a data swivel 106. The data swivel 106 may send the data to the surface equipment. Farther, the surface equipment may send data and/or power to downhole tools, the drill bit 104 and/or the drilling assembly 103. The downhole tool string 100 may comprise a downhole tool. The downhole tool may be selected from the group consisting of drill pipe, drill collars, production pipe, and reamers. The downhole tool string 100 may be subjected to downhole drilling stresses as at least a portion of the weight of the drill string 100 is placed on the drill bit 104. Those drilling stresses may be compressive stresses, tensile stresses, and/or torque stresses propagating through portions of the drill string 100.

FIG. 2 is a cross-sectional diagram of an embodiment of a portion of a downhole drill string 100. The drill string 100 may comprise a mandrel 201 with first and second ends 202, 203. The first and second ends 202, 203 may threadably connect to a first and second threaded anchor 204, 205 respectively. An intermediate sleeve assembly 206 may be held in place intermediate the first and second threaded anchors 204, 205 and around the mandrel 201. The intermediate sleeve assembly 206 may be a stabilizer. The stabilizer may be segmented both along the axis of the drill string 100 and at some point along the length of the stabilizer blade. The first and second threaded ends 202, 203 may also threadably connect to a first and second sleeve 207, 208. The intermediate sleeve assembly 206 may be a downhole tool bay adapted to hold downhole drilling tools such as sensors including, but not limited to, pressure sensors, accelerometers, hydrophones, piezoelectric devices, inclinometers, pressure transducers, magnetometers, gyroscopes, temperature sensors, gamma ray sensors, neutron sensors, seismic sensors, sonic sensors, mud logging devices, resistivity sensors, induction sensors, nuclear sensors, transmitters, receivers, imaging devices, GPS devices, Hall-effect sensors, permeability sensors, porosity sensors, vibration sensors, electrical potential sensors, geophones, proton neutron generators, batteries or the like. The downhole drilling tools within the downhole tool bay may be powered by a downhole source such as a generator, battery turbine, or combinations thereof.

The intermediate sleeve assembly 206 may be partitioned into segments. To restrict rotation of the segments of the intermediate sleeve assembly 206 relative to each other, at least one anti-rotation pin 265 may be disposed within each adjacent segment. Additionally, the anti-rotation pin may be seated within a groove formed within the mandrel 201. Thus, while the drill string 100 rotates downhole, the intermediate sleeve assembly segments may be restricted from rotation relative to each other by the anti-rotation pin 265.

The drill string 100 may experience stick slip while engaging against the side of the borehole. In embodiments where intermediate sleeve comprises a stabilizer blade, the drill string 100 may not experience as much additional torque if the intermediate sleeve assembly 206 is restricted from transmitting torque to the mandrel 201. The intermediate sleeve assembly 206 may be adapted to maximize the stabilizer blade contact with the borehole to center the drill string while drilling. In some embodiments, the stabilizer blade may house electronics, thereby improving their coupling to formation.

To ensure proper transfer of stress from the first and/or second sleeve 207, 208, the first and/or second sleeve 207, 208 may be more rigidly attached to the mandrel 201 than the intermediate sleeve assembly 206. In other embodiments, the intermediate sleeve assembly 206 may freely rotate around the mandrel 201 without the restriction of an anti-rotation pin against the mandrel 201.

FIG. 3 is a cross-sectional diagram of an embodiment of a portion of a drill string 100. In this diagram, the mandrel 201 comprises a first threaded end 202 threadably connected to a first sleeve 207. While in operation, the drill string rotates in a borehole, advancing farther into a formation. As it advances, inherent downhole stresses may be found along the drill string 100 from contact with the side of the borehole and/or stress induced by contact of the drill bit 104 with the borehole. The weight of the drill string 100 may rest on the drill bit 104 disposed at the end of the drill string resulting in compressive stresses generally along the length of the drill string 100. Those compressive stresses may be transferred from component to component.

In the embodiment of FIG. 3, the first sleeve is more rigidly attached to the mandrel that the first sleeve is connected to the intermediate sleeve. Anchor 204 may pick up a majority of the first sleeve's make-up torque. The make-up torque between anchor 204 and the intermediate sleeve may be minimal. In some embodiments, the make-up torque between the anchor and the intermediate sleeve only sufficient enough to hold the intermediate sleeve in place through the drilling process.

The stresses may be rerouted from the first sleeve 207 to the mandrel 201, bypassing the intermediate sleeve assembly 206. Farther down the drill string, the mandrel may route the stresses back into the second sleeve while preventing the stresses from being transferred into the intermediate sleeve. Arrows 300 display the path of the compressive stresses. Likewise, arrows 301 disclose rotary torque transferred from the first sleeve 207 to the mandrel 201. This may insulates the intermediate sleeve assembly 206 from a majority of the downhole stresses. By placing tools within the intermediate sleeve assembly 206, the tools may be isolated from downhole drilling stresses.

Additionally, electrical connections from downhole drilling tools located in the intermediate sleeve assembly 206 may be routed from the intermediate sleeve assembly 206 to a pressure vessel 303 through a joint-to-joint electrical connection 304. The pressure vessel 303 may be proximate the intermediate sleeve assembly 206.

In some embodiments, there are no anchors. The first and second sleeves hold the intermediate sleeve in place. The make-up is at least mostly taken up in the threads between the mandrel and the first and second sleeves, not the sleeve shoulders. FIG. 4 is a perspective cross-section of an embodiment of a portion of a drill string 100. The first sleeve 207 is seen partially removed from the drill string 100. By removing a portion of the first sleeve 207, an electronics bay 400 is revealed. The electronics bay 400 may house electronic components used in downhole drilling which may include, but is not limited to communication electronics, control electronics, acquisition electronics, pressure transducers, accelerometers, memory and/or combinations thereof. When covered, the electronics bay 400 may be sealed from drilling mud or other debris found in a downhole environment. The electronics bay 400 may be further isolated by a seal stack 401 disposed on the drill string 100.

FIG. 5 is a perspective diagram of an embodiment of a portion of a drill string 100. A downhole tool 500 may be inserted into the intermediate sleeve assembly 206 isolated from downhole drilling stresses. The downhole tool 500 may be secured into the intermediate sleeve assembly 206 by screws as shown. The downhole tool 500 may be removable. Other downhole tools 500 may be circumferentially spaced along the intermediate sleeve assembly 206.

FIG. 6 is a cross-sectional diagram of an embodiment of a portion of a drill string 100. In this embodiment, a recess 700 is formed in the first threaded anchor 204 and adapted to direct the stresses from the first threaded anchor 204 to the mandrel 201. The recess 700 may also be formed in the second threaded anchor 205 and adapted to direct the stresses from the mandrel 201 to the second threaded anchor 205 or from the second threaded anchor 205 to the mandrel 201 depending on the orientation of the drill string 100.

Whereas the present invention has been described in particular relation to the drawings attached hereto, it should be understood that other and further modifications apart from those shown or suggested herein, may be made within the scope and spirit of the present invention. 

1. A downhole tool string component, comprising; a first and second threaded end on a mandrel; the first threaded end attached to a first sleeve and the second threaded end attached to a second sleeve; an intermediate sleeve assembly disposed circumferentially around the mandrel and intermediate the first and second threaded ends; the intermediate sleeve assembly is primarily isolated from stress of the first or second sleeve.
 2. The tool string component of claim 1, wherein the intermediate sleeve assembly comprises a stabilizer blade.
 3. The tool string component of claim 1, wherein the intermediate sleeve assembly comprises at least a portion of a downhole tool bay.
 4. The tool string component of claim 1, wherein the downhole tool bay is removable.
 5. The tool string component of claim 1, wherein the mandrel comprises at least a portion of a downhole tool bay.
 6. The tool string component of claim 1, wherein the first and/or second sleeve is more rigidly attached to the mandrel than the intermediate sleeve assembly.
 7. The tool string of claim 1, wherein the first and/or second sleeve is/are disposed circumferentially around a pressure vessel.
 8. The tool string of claim 7, wherein an electronics bay is disposed intermediate the pressure vessel and the first or second sleeve.
 9. The tool string of claim 8, wherein the electronics bay comprises at least one electronics bay seal, the electronics bay seal is disposed proximate an end of the electronics bay and restricts a change in pressure within the electronics bay.
 10. The tools string of claim 8, wherein the electronics bay is disposed annularly around the pressure vessel.
 11. The tool string of claim 7, wherein the pressure vessel comprises an electrical connection with the mandrel.
 12. The tool string of claim 1, wherein the tool string comprises a first threaded anchor disposed intermediate the first sleeve and the intermediate sleeve assembly.
 13. The tool string of claim 1, wherein the tool string comprises a second threaded anchor disposed intermediate the second sleeve and the intermediate sleeve assembly.
 14. The tool string of claim 1, wherein the pressure vessel is slidably connected to the first sleeve or the second sleeve.
 15. The tool string of claim 1, wherein the intermediate sleeve assembly comprises at least two components that are restricted from rotating relative to each other by at least one anti-rotation pin.
 16. The tool string of claim 1, wherein the anti-rotation pin is at least partially disposed within a recess formed within the mandrel.
 17. A downhole tool string component, comprising; a first and second threaded end on a mandrel; the first threaded end attached to a first sleeve and the second end attached to a second sleeve; an intermediate sleeve assembly disposed circumferentially around the mandrel and intermediate the first and second threaded ends; the intermediate sleeve assembly comprises a tool bay; the tool bay is primarily isolated from stress of the first or second sleeve.
 18. The tool string of claim 17, wherein the intermediate sleeve assembly comprises a stabilizer blade. 